Portable terminal devices such as a tablet type PC and the like are used while being docked with peripheral equipment such as a keyboard, a mouse or the like in more and more cases. In such a case, in order to realize high-speed transmission, it is demanded to mount a docking connector including more contacts on a portable terminal device and peripheral equipment. For example, Patent Literature 1 recites a docking connector including a pair of connectors each having numerous contacts aligned, in which one connector is docked with the other connector.